I know HPLC is a form of column chromatography that uses high pressure to pump a sample mixture/eluent through a column. However, I'm not sure if this technique is being used to purify and isolate organic products? After doing some research, I found that automated flash chromatography systems use LPLC technique rather than HPLC. I can't understand why high pressure can't be used in these automated systems?
1$\begingroup$ Yes you can. Reverse phase is usually more useful than normal phase, MeCN/water elution. Prep HPLC has saved more of my syntheses than I care to admit to. $\endgroup$– WaylanderNov 26, 2019 at 18:38
$\begingroup$ You have analytical HPLC, semi-prep (more to do with scale than anything), preparative and then process scale chromatography. For commercial purposes, easy to remove solvents are used, which usually isn't an aqueous system. Glaxowellcome (now GSK), used this on high value products and Novasep use simulated moving bed (SMB) to deliver tonnes of material per year. $\endgroup$– BeerhunterNov 26, 2019 at 21:37
1$\begingroup$ Next to HPLC the MPLC may provide advantages of scale and resolution, too (bio-rad.com/en-us/applications-technologies/…, an application of natural product isolation link.springer.com/article/10.1007/BF02258984). $\endgroup$– ButtonwoodNov 26, 2019 at 21:50
For semiprep applications, you need larger columns, because you cannot just increase the concentration (at least not a lot) with a normal one. You can get along with an analytical column using an automated system running over the weekend, but that too fails if you want to scale up by another order of magnitude.
A HPLC pump that can run at 100x the standard flow rate is likely twenty times as expensive. The column will be much more expensive. The larger volume needs totally different safety considerations. And so on ...
As Waylander commented, you can do preparative HPLC at a pinch and save your day (or your dissertation), but to use it as a standard lab procedure is most often un..sustainable. ;)
$\begingroup$ Thanks for the explanation. This clears things up! $\endgroup$– harry86Nov 27, 2019 at 12:26